04Moving glass blob background

<main class="stage">
  <div class="bb-scene">
    <span class="bb-blob bb-blob--a"></span>
    <span class="bb-blob bb-blob--b"></span>
    <div class="bb-panel">
      <span class="bb-panel__title">Live</span>
      <span class="bb-panel__desc">Motion blurs through glass</span>
    </div>
  </div>
</main>

@use "../../../../site/static/demo-tokens" as *;

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;
$easing: linear;
$color: $subject-blue;

@include stage($stage-paper);

.bb-scene {
  position: relative;
  width: min(340px, 90vw);
  aspect-ratio: 340 / 190;
  overflow: hidden;
  border-radius: $r-card;
}

// 블롭 두 개는 배경(무대)이 아니라 이 안의 장식 레이어다 — .stage 자체 배경은 여전히 단색
// blur(40px) 는 인접 프레임 간 픽셀차를 문턱(12) 바로 아래로 뭉갰다(실측: 모든 프레임 쌍이 11~12) —
// 블러를 26px 로 낮추고 이동 폭을 키워 프레임마다 확실히 문턱을 넘게 했다
.bb-blob {
  position: absolute;
  width: 170px;
  height: 170px;
  border-radius: 50%;
  filter: blur(26px);
  opacity: .88;
}
.bb-blob--a { background: $color; top: -40px; left: -30px; animation: bb-drift-a $duration $easing infinite; }
.bb-blob--b { background: $stage-orange; bottom: -50px; right: -20px; animation: bb-drift-b $duration $easing infinite; }

@keyframes bb-drift-a {
  0%, 100% { transform: translate(0, 0); }
  50%      { transform: translate(110px, 70px); }
}
@keyframes bb-drift-b {
  0%, 100% { transform: translate(0, 0); }
  50%      { transform: translate(-90px, -55px); }
}

.bb-panel {
  position: absolute;
  inset: auto $sp-4 $sp-4 $sp-4;
  box-sizing: border-box;
  padding: $sp-4;
  border-radius: $r-control;
  background: rgba(255, 255, 255, .22);
  border: 1px solid rgba(255, 255, 255, .4);
  backdrop-filter: blur(18px) saturate(160%);
  -webkit-backdrop-filter: blur(18px) saturate(160%);
  box-shadow: $shadow-press;
  display: flex;
  flex-direction: column;
  gap: $sp-1;
  color: $subject-ink;
  font: 600 12px/1.3 -apple-system, "Segoe UI", sans-serif;
}
.bb-panel__title { font-weight: 700; font-size: 13px; }
.bb-panel__desc { opacity: .75; }

@media (prefers-reduced-motion: reduce) {
  .bb-blob { animation: none !important; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.bb-scene {
  position: relative;
  width: min(340px, 90vw);
  aspect-ratio: 340/190;
  overflow: hidden;
  border-radius: 16px;
}

.bb-blob {
  position: absolute;
  width: 170px;
  height: 170px;
  border-radius: 50%;
  filter: blur(26px);
  opacity: 0.88;
}

.bb-blob--a {
  background: #2f6df6;
  top: -40px;
  left: -30px;
  animation: bb-drift-a 2s linear infinite;
}

.bb-blob--b {
  background: #ff4d1f;
  bottom: -50px;
  right: -20px;
  animation: bb-drift-b 2s linear infinite;
}

@keyframes bb-drift-a {
  0%, 100% {
    transform: translate(0, 0);
  }
  50% {
    transform: translate(110px, 70px);
  }
}
@keyframes bb-drift-b {
  0%, 100% {
    transform: translate(0, 0);
  }
  50% {
    transform: translate(-90px, -55px);
  }
}
.bb-panel {
  position: absolute;
  inset: auto 16px 16px 16px;
  box-sizing: border-box;
  padding: 16px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.22);
  border: 1px solid rgba(255, 255, 255, 0.4);
  backdrop-filter: blur(18px) saturate(160%);
  -webkit-backdrop-filter: blur(18px) saturate(160%);
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  display: flex;
  flex-direction: column;
  gap: 4px;
  color: #17141a;
  font: 600 12px/1.3 -apple-system, "Segoe UI", sans-serif;
}

.bb-panel__title {
  font-weight: 700;
  font-size: 13px;
}

.bb-panel__desc {
  opacity: 0.75;
}

@media (prefers-reduced-motion: reduce) {
  .bb-blob {
    animation: none !important;
  }
}

import { CSSProperties } from "react";
import styles from "./GlassBlobBackground.module.scss";

type Vars = CSSProperties & {
  "--duration"?: string;
  "--color"?: string;
};

export interface GlassBlobBackgroundProps {
  duration?: string;
  color?: string;
}

export default function GlassBlobBackground({
  duration = "2000ms",
  color = "#2f6df6",
}: GlassBlobBackgroundProps) {
  const style: Vars = { "--duration": duration, "--color": color };
  return (
    <div className={styles.scene} style={style}>
      <span className={`${styles.blob} ${styles.blobA}`} />
      <span className={`${styles.blob} ${styles.blobB}`} />
      <div className={styles.panel}>
        <span className={styles.panelTitle}>Live</span>
        <span className={styles.panelDesc}>Motion blurs through glass</span>
      </div>
    </div>
  );
}